Incorporation of [2,3-13C2]- and [2,4-13C2]-D-1-deoxyxylulose into ubiquinone of Escherichia coli via the mevalonate-independent pathway for isoprenoid biosynthesis

[2,3-C-13(2)]- and [2,4-C-13(2)]-D-1-deoxyxylulose were synthesized from [2-C-13]pyruvate and [1-C-13]- or [2-C-13]-DL-glyceraldehyde using the enzyme D-1-deoxyxylulose fi-phosphate synthase from Escherichia coli which was overexpressed in this bacterium. These doubly-labeled isoprenoid precursors in the mevalonate independent route were incorporated into the ubiquinone of E., coli. (1)J C-13/C-13 coupling constants were respectively found in isoprenic units between carbon atoms derived from C-3 and C-4 of isopentenyl diphosphate using the former labeled precursor or between C-3 and C-2 using the latter, indicating that D-1-deoxyxylulose was incorporated without prior degradation into isoprenoids and confirming that the branched isoprenic skeleton resulted from a rearrangement of the straight chain from carbohydrate precursor. (C) 1997 Elsevier Science Ltd. All rights reserved.